Re: [PATCH v9 2/3] kernel.h: add to_user_ptr()

On Thu, 2016-03-17 at 15:43 -0300, Gustavo Padovan wrote:

2016-03-17 Gustavo Padovan [off-list ref]:

quoted

2016-03-17 Joe Perches [off-list ref]:

quoted

On Thu, 2016-03-17 at 14:30 -0300, Gustavo Padovan wrote:

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This function had copies in 3 different files. Unify them in
kernel.h.

This is only used by gpu/drm.

I think this is a poor name for a generic function
that would be in kernel.h.

Isn't there an include file in linux/drm that's
appropriate for this.  Maybe drmP.h

Maybe prefix this function name with drm_ too.

No, the next patch adds a user to drivers/staging (which will be moved
to drivers/dma-buf) soon. Maybe move to a different header in
include/linux/? not sure which one.

quoted

Also, there's this that might conflict:

arch/powerpc/kernel/signal_32.c:#define to_user_ptr(p)          ptr_to_compat(p)
arch/powerpc/kernel/signal_32.c:#define to_user_ptr(p)          ((unsigned long)(p))

Right, I'll figure out how to replace these two too.

The powerpc to_user_ptr has a different meaning from the one I'm adding
in this patch. I propose we just rename powerpc's to_user_ptr to
__to_user_ptr and leave the rest as is.

I think that's not a good idea, and you should really check
this concept with the powerpc folk (added to to:s and cc:ed)

If it were really added, then the function meaning is incorrect.

This is taking a u64, casting that to (unsigned long/uint_ptr_t),
then converting that to a user pointer.

Does that naming and use make sense on x86-32 or arm32?